In general, coated abrasive products are known to have abrasive particles adherently bonded to a flexible backing. It is generally known to stratify the abrasive particles and binders, such as in coated abrasive articles, in such a way as to basically segregate the abrasive particles between an underlying binder and an overlaying binder.
More typically, abrasive products have a backing, abrasive particles, and a binder which operates to bond or hold the abrasive particles to the backing. For example, a typical coated abrasive product has a backing that is first coated with a binder, commonly referred to as a "make coat", and then the abrasive particles are applied to the make coat. The application of the abrasive particles to the make coat typically involves electrostatic deposition or a mechanical process which maximizes the probability that the individual abrasive particles are positioned with their major axis oriented perpendicular to the backing surface. As so applied, the abrasive particles optimally are at least partially embedded in the make coat that is then generally solidified or set (such as by a series of drying or curing ovens) to a state sufficient to retain the adhesion of abrasive particles to the backing.
Optionally, after precuring or setting the make coat, a second binder, commonly referred to as a "size coat", can be applied over the surface of the make coat and abrasive particles, and, upon setting, it further supports the particles and enhances the anchorage of the particles to the backing. Further, a "supersize" coat, which may contain grinding aids, anti-loading materials or other additives can be applied over the cured size coat. In any event, once the size coat and supersize coat, if used, has been cured, the resulting coated abrasive product can be converted into a variety of convenient forms such as sheets, rolls, belts, and discs.
Coated abrasives are used to abrade a variety of workpieces including metal, metal alloys, glass, wood, paint, plastics, body filler, primer, etc. In abrading certain workpieces, for example, wood, paint, body filler, primer, and plastics, the coated abrasive has a tendency to "load." "Load" or "loading" are terms used in the industry to describe the debris, or swarf, that is abraded away from the workpiece surface that subsequently becomes lodged between the abrasive particles of the abrasive article. Loading is generally undesirable because the debris lodged between abrasive particles inhibits the cutting ability of the abrasive article.
One solution to the loading problem is to apply a coating to an abrasive article so that it is available at the interface between the abrasive article and the workpiece surface to inhibit loading. For example, U.S. Pat. No. 2,768,886 (Twombly et al.) and U.K. Patent No. 712,718 each describe a metal stearate or palmitate applied to the surface of an abrasive article. U.S. Pat. Nos. 2,893,854 and 3,619,150 (both to Rinker et al.) each describe a metallic water-insoluble soap of a saturated fatty acid having from 16 to 18 carbon atoms that is applied to an abrasive article. U.S. Pat. No. 4,396,403 (Ibrahim) describes an abrasive article including a coating containing a material selected from the group consisting of phosphoric and condensed phosphoric acids and partial esters, including amine salts thereof, tetraorganyl ammonium salts having at least one long organyl group containing at least eight carbon atoms, and mixtures thereof. Other materials that have been applied to an abrasive article include, for example, a quaternary ammonium salt having from about 15 to about 35 carbon atoms (U.S. Pat. No. 4,973,338 to Gaeta et al.) and a lithium salt of a saturated fatty acid having 4 to 22 carbon atoms (U.S. Pat. No. 4,988,554 to Peterson et al.). Other antiloading components are also described by Law et al. in U.S. Pat. Nos. 5,667,542 and 5,704,952.